Ceramic processing for the direct manufacture of customized labial and lingual orthodontic brackets

ABSTRACT

A method of manufacturing customized ceramic labial/lingual orthodontic brackets by digital light processing, said method comprises measuring dentition data of a profile of teeth of a patient, wherein measuring dentition data is performed using a CT scanner or intra-oral scanner, based on the dentition data, creating a three dimensional computer-assisted design (3D CAD) model of the patient&#39;s teeth using reverse engineering, and saving the 3D CAD model on a computer, designing a 3D CAD bracket structure model for a single labial or lingual bracket structure, importing the 3D CAD bracket structure model into a Digital Light Processing (DLP) machine, directly producing the bracket by layer manufacturing.

BACKGROUND OF THE INVENTION 1. Field of the Invention

An embodiment of present invention relates generally to themanufacturing of ceramic labial/lingual orthodontic brackets forstraightening the teeth and correcting malocclusion. More specifically,an embodiment of the invention relates to the methodology of directmanufacture of customized labial/lingual orthodontic brackets by usinglithography-based ceramic manufacturing (LCM) or by digital lightprocessing of ceramics (DLP) additive manufacturing (AM) technology.

2. Description of the Related Art

Orthodontics has been widely adapted in clinics to correct malocclusionand straighten teeth. The traditional method is to adhere preformedbrackets onto the teeth and run elastic metal wires of round, square, orrectangular cross-sectional shape through the bracket slots to providethe driving force. The adaptation of the bracket to the individual toothis performed by filling the gap between the tooth surface and bracketsurface with adhesive. This thereby bonds the bracket to the tooth suchthat the bracket slot, when the teeth are moved to their final position,lies in a near flat (depending on manufacturing accuracy) horizontalplane.

Preformed edgewise brackets may have no prescription, requiringadjustment of the archwire. Alternatively, the edgewise brackets mayhave an idealized prescription of angulation, inclination, or in/outvariation for specific teeth in what is referred to as a “straight-wireappliance”. Because the bracket pad is typically not custom made for anindividual patient's tooth, the clinician is responsible for the bracketplacement, which may introduce a source of error, which commonlyincreases patient visits and overall treatment time. These brackets aretypically off-the-shelf products, and currently there are no customdesigned ceramic brackets available commercially. A misplacement inbonding a bracket to a tooth can be corrected by compensation bends inthe wire or by debonding and repositioning of the bracket, both of whichincrease time and cost. Custom metal lingual brackets are currentlyavailable that are fabricated at a central location from 3D scans orimpressions of the dentition and mailed back to the clinician andtransferred to the patient via indirect bonding. Selective laser melting(SLM) is a 3DAM technique that has been used to create custom metallingual brackets (for example, see U.S. Pat. No. 8,694,142 B2), but thistechnique suffers from insufficient resolution and surface finish. Whiletrue custom labial brackets have been used, custom positioning of astandard, non-custom bracket can be created via indirect bonding whichitself has inherent error within the bracket itself. Many current truecustom labial systems (SURESMILE™ Inc.) rely heavily on putting custombends in the wire based on a 3D scan rather than creating a truestraight-wire appliance. For example, U.S. Pat. No. 8,690,568 providesfor a method to weld a metal bracket slot to a stock metal bracket baseinto a custom position, but does not describe a method for creating acustom bracket base or to create an aesthetic, non-metal bracket. Thesepartially custom metal brackets suffer from inaccuracy in slot positionand premature debonding due a stock bracket base that doesn't match thetooth morphology, and are unappealing to older patients who prefer tohave non-metal brackets for aesthetic concerns.

Ceramic brackets have been commercially available and studied since the1980s and are a desirable material compared to metal brackets due totheir excellent esthetics, resistance to creep, rigidity,biocompatibility, corrosion resistance, stability in the oralenvironment and non-toxic nature. Currently, no system for creating anesthetic custom lingual or labial ceramic orthodontic brackets exists,and no custom bracket system exists that may be fabricated 100%in-office by trained members of a private orthodontic practice.

A need arises for more efficient and accurate techniques for creatingcustom lingual and labial ceramic orthodontic brackets, and moreaesthetic labial brackets

SUMMARY OF THE INVENTION

An embodiment of the present invention provides improved techniques forcreating custom lingual or labial ceramic orthodontic brackets, andwhich provides the capability for in office fabrication of suchbrackets.

An embodiment of the present invention may be used to solve problemsoccurring in the current manufacturing techniques of straight wireappliance orthodontic brackets. For example, in one embodiment, it mayprovide a direct manufacturing method of customized lingual/labialbrackets by utilizing digital light processing (DLP). Examples of itemsthat may be produced include customized brackets according to individualfeatures, and which include more adhesive brackets on the tooth surfacebecause of the high manufacturing accuracy. DLP additive manufacturingAM may be performed in a device small enough to comfortably fit in aprivate orthodontic lab and can currently be obtained at a reasonableprice, given the market price and in-office volume for non-custom andcustom brackets.

For example, in one embodiment, a method of manufacturing customizedceramic labial/lingual orthodontic brackets by digital light processingmay comprise measuring dentition data of a profile of teeth of apatient, based on the dentition data, creating a three dimensionalcomputer-assisted design (3D CAD) model of the patient's teeth usingreverse engineering, and saving the 3D CAD model on a computer,designing a 3D CAD bracket structure model for a single labial orlingual bracket structure, importing data related to the 3D CAD bracketstructure model into a Digital Light Processing (DLP) machine, directlyproducing the bracket in the DLP machine by layer manufacturing.

The 3D CAD bracket structure model may include data representing atleast a) the bracket pad (bottom plate) that has recesses and/orundercuts into the bonding surface of the bracket, to contact aparticular tooth's surfaces, b) slots for positioning according to theorthodontia needs of the patient, c) a bracket material, d) theparticular tooth's profile, and e) a bracket guide to guide3-dimensional placement of the bracket onto the tooth.

The DLP machine may comprise a molding compartment comprising a platformand a plunger to directly produce the bracket by layer manufacturing, amaterial compartment, and an LED light source for digital lightprocessing, wherein the bracket is produced by layer manufacturing usingslicing software to separate the 3D CAD bracket structure model intolayers and to get a horizontal section model for each layer so that ashape of each layer produced by the DLP machine is consistent with the3D CAD structure data. The DLP machine may comprise a vat adapted tohold the bracket during manufacturing, a horizontal build platformadapted to be held at a settable height above the vat bottom, anexposure unit, adapted to be controlled for position selective exposureof a surface on the horizontal build platform with an intensity patternwith predetermined geometry, a control unit, adapted to receive the 3DCAD bracket structure model and, using the 3D CAD bracket structuremodel to polymerize in successive exposure steps layers lying one abovethe other on the build platform, respectively with predeterminedgeometry, by controlling the exposure unit, and to adjust, after eachexposure step for a layer, a relative position of the build platform tothe vat bottom, to build up the object successively in the desired form,which results from the sequence of the layer geometries. The exposureunit may further comprise a laser as a light source, a light beam ofwhich successively scans the exposure area by way of a movable mirrorcontrolled by the control unit.

Directly producing the bracket by layer manufacturing may furthercomprise in an apparatus comprising a vat with an at least partiallytransparently or translucently formed horizontal bottom, into whichlight polymerizable material can be filled, a horizontal build platformadapted to be held at a settable height above the vat bottom, anexposure unit adapted to be controlled for position selective exposureof a surface on the build platform with an intensity pattern withpredetermined geometry, comprising a light source refined bymicromirrors to more precisely control curing, a control unit adaptedfor polymerizing in successive exposure steps layers lying one above theother on the build platform, controlling the exposure unit so as toselectively expose a photo-reactive slurry in the vat, adjusting, aftereach exposure for a layer, a relative position of the build platform tothe vat bottom, and building up the bracket successively in the desiredform, resulting from the sequence of the layer geometries. The exposureunit may further comprise a laser as a light source, a light beam ofwhich successively scans the exposure area by way of a movable mirrorcontrolled by the control unit.

A scanning accuracy may be less than 0.02 mm. A manufacturing accuracymay be from 5 to about 60 and wherein the accuracy may be achieved byusing a between layer additive error compensation method that predictsan amount of polymerization shrinkage. Manufactured layers of thebracket comprise a material selected from the group consisting of highstrength oxide ceramics including Aluminum Oxide (Al₂O₃) and ZirconiumOxide (ZrO2) and may be mono- or polycrystalline ceramic. The smallestlength from a bracket pad to slot depth may be from 0.2 mm-3 mmdepending on the bracket offset required and desire to reduce thebracket profile for patient comfort.

The 3D CAD model may be saved as an .stl file. The thickness of themanufactured layers may be from 5 to 100 micrometers (μm). Differentlight curing strategies (LCSs) and depths of cure (Cd) may be used. Aselection of material for producing layers of the bracket may be basedon different force demands. The printed bracket guides may have a singlebracket attachment for a single bracket. An adhesive material may beused to hold the bracket on the ceramic archwire. The adhesive materialmay be sticky wax. Indirect bonding/custom bracket placement may occurvia a tray (for example, a silicone based or vacuum formed tray) thatcarries the said custom ceramic brackets to the ideal tooth location.

The printed brackets may have a metal insert that contacts the archwirein the slot. The printed brackets may be of a traditional twin design orare modified to be self-ligating or active ligating and are designed toaccommodate 0.018 in or 0.022 in archwires in the slot, but slot heightmay vary from 0.018-0.022. The bracket angulation, offsets, torque, andprescription may be determined based on a chosen treatment. Thestructural properties of the base may be altered to facilitate easierdebonding of the bracket following treatment. A part of the bracket maybe a pre-formed green ceramic body that functions to decrease the timeand complexity of the printed bracket. The method may further compriseproducing a bracket guide comprising a rigid ceramic rectangulararchwire or other archform that dictates a position of each bracket on atooth in every plane with at least two occlusal/incisal supports adaptedto help place brackets via an indirect bonding system. A part of thebracket that holds or connects the bracket to the tooth surface may bedesigned based on a surface profile of the tooth. The bracket may have acolor that is matched to a color of a tooth to which the bracket is tobe attached. The bracket may be clear. The bracket may have a selectedcolor unrelated to a color of a tooth to which the bracket is to beattached.

The DLP machine may include a light source that is a laser or LED lightsource. A light source of the DLP machine may radiate a wavelengthbetween 400 and 500 nm. The DLP machine may include a digital lightprocessing chip as light modulator. The digital light processing chipmay be a micromirror array or an LCD array.

Measuring dentition data may be performed using a CT scanner, intra-oralscanner, a coordinate measuring machine, a laser scanner, or astructured light digitizers. Measuring dentition data may be performedby conducting 3D scanning on a casted or 3D printed teeth model.

The light-polymerizable material may be selected from the groupconsisting of high strength Oxide ceramics including Aluminum Oxide(Al2O3) and Zirconium Oxide (ZrO2). 36. A slot position relative to thetooth may be customized by manufacturing a custom base or bymanufacturing a custom slot position where a base is unchanged.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary flow diagram of an embodiment of a process fordirect manufacturing lingual or labial orthodontic brackets.

FIG. 2 illustrates an example of a single bracket bracket-guide showinga lower molar and upper incisor tooth.

FIG. 3 illustrates an example of a bracket guide that may be a rigidceramic rectangular archwire that engages each bracket in every planewith two or more occlusal supports.

FIG. 4 illustrates an example of designed brackets having a custombracket pad that is matched to the lingual or labial surface of thetooth.

FIG. 5 illustrates a side view of an example of a designed bracket.

FIG. 6 illustrates a top view of an example of a designed bracket.

FIG. 7 is an exemplary block diagram of an embodiment of a computersystem in which the processes of the present invention may beimplemented.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention provides improved techniques forcreating custom lingual or labial ceramic orthodontic brackets, andwhich provides the capability for in-office fabrication of suchbrackets.

An exemplary flowchart of an embodiment a direct manufacturing process100 of lingual or labial orthodontic brackets by digital lightprocessing is shown in FIG. 1. The process begins with 102, in whichdentition data is measured and the parameters of the tooth profile areanalyzed. For example, such measurement may use CT layer scanning anon-contact 3D scanner or an intra-oral scanner directly on thepatient's teeth, or may use 3D readings on a teeth model previously castor 3D printed using a coordinate measuring machine, a laser scanner, ora structured light digitizers. The scanning accuracy of such techniquesis typically less than 0.02 mm.

In 104, based on the given dentition data, a 3D CAD model of themeasured teeth is constructed based on the dentition data and saved inthe computer in a typical file format, such as the .stl file format. Theexterior structure of teeth is complicated, usually including irregularcurves. The software may then be used to re-arrange the teeth in themodel to the desired treatment outcomes that may be based on thelong-axis of a tooth.

In 106, additional information, such as the desired torque, offset,angulation of select brackets and occlusal/incisal coverage forplacement guide is entered.

In 108, the bracket (or brackets) is designed by the software based onthe input 3D CAD model of the measured teeth, the model of the desiredtreatment outcomes, and the input additional information. The output ofthe design process may be a 3D CAD model. Such a 3D CAD model may bedesigned for a single lingual/labial bracket structure, including thebracket guide and bracket pad in contact with teeth surface, as well asthe slots for the ideal position according to the orthodontiarequirement, ceramic bracket material, and tooth profile. A bracketguide may be a single bracket pad for a single bracket or may be a rigidceramic rectangular archwire with two or more occlusal supports, whichare designed to help place brackets via indirect bonding. If the guideis for a single bracket, the bracket guide may be printed such that itis serrated at its interface with the bracket such that it may besnapped or drilled off upon bonding.

3D CAD bracket structure models of labial or lingual brackets may bedesigned by computer according to the orthodontic requirements,material, and teeth morphology. Referring to FIG. 2, which illustratesan example of a single bracket bracket-guide showing a lower molar andupper incisor tooth with a connected, but detachable bracket guide thatmay have a weak point or serration at the guide-bracket interface. Thebracket model design may include the bracket pad 202 (bonding pad)contacting with the tooth surface, as well as the custom bracket slotlocated on its ideal position and a bracket guide 204. A bracket guide204 may be a single bracket pad 202 attached to a single bracket guide204, as shown in FIG. 2. Alternatively, as shown in FIG. 3, a bracketguide may be a rigid ceramic rectangular archwire that engages eachbracket in every plane with two or more occlusal supports 304 that aredesigned to help place brackets via indirect bonding. The horizontalceramic wire and the occlusal/incisal pads control for verticalposition. Vertical notches such as 306 on the wire control thehorizontal position of the bracket on the ceramic wire.

3D CAD bracket structure models are processed to generate manufacturingcontrol data for use by the production equipment. For example, where DLPequipment is used to produce the brackets, the software slices the 3DCAD bracket structure models to separate it into thin layers and get thehorizontal section model for each layer. Based on this section model,the DLP equipment can directly produce ceramic brackets, ensuring theshape of each layer is consistent to the 3D CAD structure data. Forexample, the thickness of such layers may be about 20 μm to about 50 μm(micrometers or microns) with a manufacturing accuracy of about 5 μm toabout 10 μm by using between-layer additive error compensation.

Returning to 108 of FIG. 1, the 3D CAD bracket structure model istransmitted to or imported into a 3D production machine, such as a DLPmachine and the ceramic brackets are produced. In the case of DLP, thebrackets may be produced by digital light processing directly.

Digital light processing (DLP) is another 3D additive manufacturing (AM)process that works by stacking layers of a photocurable resin with anAluminum Oxide (Al₂O₃) or Zirconium Oxide (ZrO₂) solid loading, andfollowed by a thermal debinding and sintering step. The higherresolution of this process is made possible by the LED light's digitalmirror device (DMD) chip and optics used. Lithography-based ceramicmanufacturing (LCM) has improved this process making it more accuratewith higher resolution (40 μm) and rigidity. The new LCM processinvolves the selective curing of a photosensitive resin containinghomogenously dispersed oxide or glass ceramic particles that can befabricated at very high resolution due to imaging systems which enablethe transfer of layer information by means of ever-improving LEDtechnology.

In 110, post-processing may then be applied. For example, a thermaltreatment (for binder burnout) and a sintering process may be applied toachieve optimal or improved ceramic density. For example, the debindingand sintering phase may include removing the green bracket from thedevice, exposing the blank to a furnace to decompose the polymerizedbinder (debinding), and sintering of the ceramic material.

The pad (bonding pad) of the bracket may be less than 0.4 mm thick. Thebracket placement guide may be placed occlusally/incisally to guide thecorrect placement of the bracket on the tooth. Examples of raw materialsof the brackets may include powder of high strength oxide ceramics suchas Aluminum Oxide (Al₂O₃) and Zirconium Oxide (ZrO₂), or other highstrength ceramic compositions.

The base of bracket may be adhered to the tooth surface and the bracketslot may be matched to the archwire. According to requirements ofmechanical properties, different composition of material may be requiredfor the layers during the DLP manufacturing process. After being builtup, the brackets may have a gradient and better performance.

Further, the bracket surface may be processed based on clinical demand.

Returning to FIG. 1, in 112, the bracket is ready to be placed.

Typically, the thickness of the bracket pad may less than 1 mm forlingual brackets and less than 1.5 for labial brackets. Suitablemanufacturing materials may include high-strength Oxide ceramics, suchas Aluminum Oxide (Al₂O₃) and Zirconium Oxide (ZrO₂). The bracket padmay be adhered to the tooth surface with well-known dental adhesives.The bracket slot may be matched to the archwire, which may be straightor custom bent. Depending upon the manufacturing process used, differentceramics or composition of powder may be required for the layers. Forexample, if a selective laser melting manufacturing process is used, anLED light source may be used for the selective curing of aphotosensitive resin containing the oxide or glass ceramic particles.Different layers may use different ceramics or compositions of powder.

The bracket pad, which holds or connects the bracket to the toothsurface, may be designed specifically according to the tooth surfaceprofile, instead of a generalized gridding pattern. The customizedbrackets can meet individual case demand, such as increased anteriorlabial crown torque required in certain types of cases. For example, asshown in FIG. 4, the curve on tooth surface and the designed bracket,the tooth side of the bracket (bracket pad) is matched to the lingual orlabial surface of the tooth, for example for lingual bracket 402 andlabial bracket 404.

A side view of an exemplary printed bracket 500 is shown in FIG. 5. Theslot 502 on the bracket may have high accuracy in size, shape, andangler, and may have low thickness and is designed to accommodate arectangular wire when completely filled. Slot 502 may be manufactured toany desired size and shape, but typically, slot 502 is manufactured witha greater depth than height or width. The base 504 of the bracket mayhave different height because of the selected material or desiredorthodontic result. Likewise, the pad 506 of the bracket may highlymatch the tooth surface and maximize the tooth contact surface. This mayallow for more accurate bracket placement by the clinician and betterbond approximation to the tooth. Also, because each slot has its ownposition and shape to cooperate with the archwire, twisting error may beminimized and improved orthodontic result may be actualized. In a numberof embodiments, these features may be manufactured as one piece and thatthe customization of the slot relative to the tooth may be a function ofthe slot changing position or the bracket base moving. In manyembodiments, no machining of the features is required to produce asuitable bracket.

A top view of an exemplary printed bracket 600 is shown in FIG. 6.Bracket guides may be printed that extend an arm occlusally/incisallythat attaches to a pad that covers enough of the structure of the tooth602 (mesial/distal of occlusal/incisal surface or marginal ridge) suchthat brackets are placed in the computer-generated ideal location tocreate the desired tooth position. A bracket guide may be a singlebracket pad for a single bracket or may be a rigid ceramic rectangulararchwire that engages each bracket in every plane with two or moreocclusal supports that are designed to help place brackets via indirectbonding. The horizontal ceramic wire and the occlusal/incisal padscontrol for vertical position, vertical notches on the wire control thehorizontal position of the bracket on the ceramic wire guide.

Bracket 600 may further include an attachment such as a hook 604 thatprovides the capability to use additional delivery systems such aselastomers, springs or other attachments that create vectors of force.In a number of embodiments, these features may be manufactured as onepiece, protruding from any predesigned area to create the proper forcevectors desired, and no machining of the features is required to producea suitable bracket.

Using the lithography-based digital light processing technique can turnthe designed model into a ceramic product rapidly. The bracketmanufacturing involves few steps and can be done on site, saving timeand cost.

The described techniques may be used to manufacture brackets fromvarious Oxide ceramics and light-curable materials such as AluminumOxide (Al₂O₃) and Zirconium Oxide (ZrO₂).

The described techniques may be used to attain a true straight wireappliance where bracket placement accuracy is improved, thus reducingtreatment time and error; or may also be used in conjunction with acustom-bent arch wire to achieve ideal results.

Patients currently pay higher fees for white-colored ceramic bracketsover metal due to their increased esthetics. For example, many patientsdesire a bracket that matches the color of the tooth to which thebracket is attached. This may cause the bracket to be less visible andprovide improved appearance. As another example, embodiments of thepresent invention may provide the capability to produce clear brackets,which may provide still improved appearance. Additionally, embodimentsof the present invention may provide the capability to produce bracketsin almost any color desired or selected, for example, in bright colorsfor use in children and some adults. Likewise, embodiments of thepresent invention may provide the capability to produce brackets havingvisible shapes that are not dictated by function, such as in the shapeof animals, vehicles, toys, etc., for example, for use in children andsome adults.

The described techniques may be made cost-effective to the point wherean individual orthodontic practice could purchase the required equipmentand software. This would provide the capability to simplify theirbracket inventory instead of stocking brackets of differentprescriptions.

Digital light processing (lithography-based) of ceramics has manyadvantages for orthodontic bracket fabrication over selective lasersintering/melting (SLM) which uses thermal energy, and 3-D printing(3DP) systems that use a binder and polymer-derived ceramics (PDCs). Forexample, DLP may provide higher surface quality, better objectresolution, and improved mechanical properties. PDCs structured usinglight in a stereolithographic or mask exposure process may also be usedas a ceramic AM method for bracket fabrication.

Custom lingual brackets may be fabricated by this method, which mayreceive a pre-bent customized archwire as described by US 2007/0015104A1. Custom labial brackets may also receive pre-bent wires.

The procedure for the layering additive manufacturing (AM) methodologyof the labial/lingual orthodontic brackets by lithography-based DLP(U.S. Pat. No. 8,623,264 B2) is as follows.

An example of a lithography-based DLP process is described in U.S. Pat.No. 8,623,264 B2, which is incorporated herein by reference, but may bebriefly summarized as follows: a light-polymerizable material, thematerial being located in at least one trough, having a particularlylight-transmissive, horizontal bottom, is polymerized by illumination onat least one horizontal platform, the platform having a pre-specifiedgeometry and projecting into a trough, in an illumination field, whereinthe platform is displaced vertically to form a subsequent layer,light-polymerizable material is then added to the most recently formedlayer, and repetition of the foregoing steps leads to the layeredconstruction of the orthodontic bracket in the desiredprescription/mold, which arises from the succession of layer geometriesdetermined from the CAD software. The trough can be shifted horizontallyto a supply position, and the supply device brings light-polymerizablematerial at least to an illumination field of the trough bottom, beforethe at least one trough is shifted to an illumination position in whichthe illumination field is located below the platform and above theillumination unit, and illumination is carried out, creating a “greenbracket”.

The light-polymerizable material or photo-reactive suspension (slurry)can be prepared based on commercially available di- and mono-functionalmethacrylates. An example material might be a slurry blend of 0.01-0.025wt % of a highly reactive photoinitiator, 0.05-6 wt % a dispersant, anabsorber, and 2-20 wt % of a non-reactive diluent. A solid loading ofhigh strength Oxide ceramics such as Aluminum Oxide (Al₂O₃) andZirconium Oxide (ZrO₂) powder can be used, but this process may extendto other ceramic materials.

An exemplary block diagram of a computer system 700, in which theprocesses shown above may be implemented, is shown in FIG. 7. Computersystem 700 is typically a programmed general-purpose computer system,such as a personal computer, workstation, server system, andminicomputer or mainframe computer. Computer system 700 includes one ormore processors (CPUs) 702A-702N, input/output circuitry 704, networkadapter 706, and memory 708. CPUs 702A-702N execute program instructionsin order to carry out the functions of embodiments of the presentinvention. Typically, CPUs 702A-702N are one or more microprocessors,such as an INTEL PENTIUM® processor. FIG. 7 illustrates an embodiment inwhich computer system 700 is implemented as a single multi-processorcomputer system, in which multiple processors 702A-702N share systemresources, such as memory 708, input/output circuitry 704, and networkadapter 706. However, the present invention also contemplatesembodiments in which computer system 700 is implemented as a pluralityof networked computer systems, which may be single-processor computersystems, multi-processor computer systems, or a mix thereof.

Input/output circuitry 704 provides the capability to input data to, oroutput data from, computer system 700. For example, input/outputcircuitry may include input devices, such as keyboards, mice, touchpads,trackballs, scanners, etc., output devices, such as video adapters,monitors, printers, etc., and input/output devices, such as, modems,etc. Network adapter 706 interfaces device 700 with a network 710.Network 710 may be any public or proprietary LAN or WAN, including, butnot limited to the Internet.

Memory 708 stores program instructions that are executed by, and datathat are used and processed by, CPU 702 to perform the functions ofcomputer system 700. Memory 708 may include, for example, electronicmemory devices, such as random-access memory (RAM), read-only memory(ROM), programmable read-only memory (PROM), electrically erasableprogrammable read-only memory (EEPROM), flash memory, etc., andelectro-mechanical memory, such as magnetic disk drives, tape drives,optical disk drives, etc., which may use an integrated drive electronics(IDE) interface, or a variation or enhancement thereof, such as enhancedIDE (EIDE) or ultra-direct memory access (UDMA), or a small computersystem interface (SCSI) based interface, or a variation or enhancementthereof, such as fast-SCSI, wide-SCSI, fast and wide-SCSI, etc., orSerial Advanced Technology Attachment (SATA), or a variation orenhancement thereof, or a fiber channel-arbitrated loop (FC-AL)interface.

The contents of memory 708 varies depending upon the function thatcomputer system 700 is programmed to perform. In the example shown inFIG. 7, memory contents that may be included in a system in which acontent analysis platform is implemented are shown. However, one ofskill in the art would recognize that these functions, along with thememory contents related to those functions, may be included on onesystem, or may be distributed among a plurality of systems, based onwell-known engineering considerations. Embodiments of the presentinvention contemplate any and all such arrangements.

In the example shown in FIG. 7, memory 708 may include dentition datameasurement routines 712, 3D CAD teeth model construction routines 714,3D CAD teeth model editing routines 716, bracket design routines 718,manufacturing control data generation routines 720, and operating system722. Dentition data measurement routines 712 may obtain and processdentition data, such as may be generated by CT layer scanning or anon-contact 3D scanner directly on the patient's teeth, or uses 3Dreadings on the teeth model previously cast. 3D CAD teeth modelconstruction routines 714 may construct a 3D CAD model of the measuredteeth based on the dentition data. 3D CAD teeth model editing routines716 may be used to re-arrange the teeth in the model to the desiredtreatment outcomes and may additionally be used to accept additionalinformation, such as the desired torque, offset, angulation of selectbrackets and occlusal/incisal coverage for placement guide. Bracketdesign routines 718 may be used to design and generate a 3D CAD modelbased on the input 3D CAD model of the measured teeth, the model of thedesired treatment outcomes, and the input additional information.Manufacturing control data generation routines 720 may be used togenerate manufacturing control data for use by the production equipment.Operating system 722 provides overall system functionality.

It is to be noted that additional functionality may be implemented inend user devices, such as end user devices 104 shown in FIG. 1. End usersystems may be computer systems having a structure similar to that shownin FIG. 7. Such end user systems may include geometric analysis routinesto perform geometric analysis of a location of an advertisement orcontent, such as may be performed by step 302 of FIG. 3. Likewise, suchend user systems may include resource-based analysis routines todetermine whether a computer is optimizing an advertisement or contentfor display on the screen, such as may be performed by step 302 of FIG.3.

As shown in FIG. 7, an embodiment of the present invention contemplatesimplementation on a system or systems that provide multi-processor,multi-tasking, multi-process, and/or multi-thread computing, as well asimplementation on systems that provide only single processor, singlethread computing. Multi-processor computing involves performingcomputing using more than one processor. Multi-tasking computinginvolves performing computing using more than one operating system task.A task is an operating system concept that refers to the combination ofa program being executed and bookkeeping information used by theoperating system. Whenever a program is executed, the operating systemcreates a new task for it. The task is like an envelope for the programin that it identifies the program with a task number and attaches otherbookkeeping information to it. Many operating systems, including Linux,UNIX®, OS/2®, and Windows®, are capable of running many tasks at thesame time and are called multitasking operating systems. Multi-taskingis the ability of an operating system to execute more than oneexecutable at the same time. Each executable is running in its ownaddress space, meaning that the executables have no way to share any oftheir memory. This has advantages, because it is impossible for anyprogram to damage the execution of any of the other programs running onthe system. However, the programs have no way to exchange anyinformation except through the operating system (or by reading filesstored on the file system). Multi-process computing is similar tomulti-tasking computing, as the terms task and process are often usedinterchangeably, although some operating systems make a distinctionbetween the two.

It is important to note that while aspects of the present invention maybe implemented in the context of a fully functioning data processingsystem, those of ordinary skill in the art will appreciate that theprocesses of an embodiment of the present invention are capable of beingdistributed in the form of a computer program product including acomputer readable medium of instructions. Examples of non-transitorycomputer readable media include storage media, examples of whichinclude, but are not limited to, floppy disks, hard disk drives,CD-ROMs, DVD-ROMs, RAM, and, flash memory.

Although specific embodiments of the present invention have beendescribed, it will be understood by those of skill in the art that thereare other embodiments that are equivalent to the described embodiments.Accordingly, it is to be understood that the invention is not to belimited by the specific illustrated embodiments, but only by the scopeof the appended claims.

What is claimed is:
 1. A method of manufacturing customized ceramic labial/lingual orthodontic brackets by digital light processing, said method comprising: measuring dentition data of a profile of teeth of a patient, wherein a scanning accuracy of the measuring is less than 0.02 mm; based on the dentition data, creating a three dimensional computer-assisted design (3D CAD) model of the patient's teeth using reverse engineering; designing a 3D CAD bracket structure model for a single labial or lingual orthodontic bracket structure including a slot; importing data related to the 3D CAD bracket structure model into a photo-reactive slurry-based Digital Light Processing (DLP) machine; directly producing the ceramic bracket in the DLP machine by layer manufacturing, wherein a manufacturing accuracy is from 2 to about 20 μm, and wherein a thickness of the manufactured layers is from 5 to 100 micrometers (μm) based on the resolution requirements of the bracket area.
 2. The method of claim 1, wherein the 3D CAD bracket structure model includes data representing at least a) the bracket pad (bottom plate) that has recesses and/or undercuts into the bonding surface of the bracket custom shaped to fit the negative of a labial/lingual tooth surface, and contact a particular area of a tooth surface, b) slots for positioning according to the orthodontia needs of the patient, c) a bracket material, d) the particular tooth's profile, and e) a bracket guide to guide 3-dimensional placement of the bracket onto the tooth.
 3. The method of claim 1, wherein the DLP machine comprises: a molding compartment comprising a platform and a plunger to directly produce the bracket by layer manufacturing; a material compartment; and an LED light source for digital light processing, wherein the bracket is produced by layer manufacturing using slicing software to separate the 3D CAD bracket structure model into layers and to get a horizontal section model for each layer so that a shape of each layer produced by the DLP machine is consistent with the 3D CAD structure data.
 4. The method of claim 1, wherein the DLP machine comprises: a vat adapted to hold the bracket during manufacturing; a horizontal build platform adapted to be held at a settable height above the vat bottom; an exposure unit, adapted to be controlled for position selective exposure of a surface on the horizontal build platform with an intensity pattern with predetermined geometry; a control unit, adapted to receive the 3D CAD bracket structure model and, using the 3D CAD bracket structure model to: polymerize in successive exposure steps layers lying one above the other on the build platform, respectively with predetermined geometry, by controlling the exposure unit, and to adjust, after each exposure step for a layer, a relative position of the build platform to the vat bottom, to build up the object successively in the desired form, which results from the sequence of the layer geometries.
 5. The method of claim 4, wherein the exposure unit further comprises a laser as a light source, a light beam of which successively scans the exposure area by way of a movable mirror controlled by the control unit.
 6. The method of claim 1, wherein directly producing the bracket by layer manufacturing further comprises: in an apparatus comprising: a vat with an at least partially transparently or translucently formed horizontal bottom, into which light polymerizable material can be filled, a horizontal build platform adapted to be held at a settable height above the vat bottom, an exposure unit adapted to be controlled for position selective exposure of a surface on the build platform with an intensity pattern with predetermined geometry, comprising a light source refined by micromirrors to more precisely control curing, a control unit adapted for polymerizing in successive exposure steps layers lying one above the other on the build platform; controlling the exposure unit so as to selectively expose a photo-reactive slurry in the vat; adjusting, after each exposure for a layer, a relative position of the build platform to the vat bottom; and building up the bracket successively in the desired form, resulting from the sequence of the layer geometries.
 7. The method of claim 6, wherein the exposure unit further comprises a laser as a light source, a light beam of which successively scans the exposure area by way of a movable mirror controlled by the control unit.
 8. The method of claim 1, wherein the manufacturing accuracy is achieved by using a between layer additive error compensation method that predicts an amount of polymerization shrinkage, so as to avoid divergent or convergent slot walls, achieve desired slot height, or avoid errors in the bracket base morphology.
 9. The method of claim 8, wherein manufactured layers of the bracket comprise a material selected from the group consisting of high strength oxide ceramics including Aluminum Oxide (Al2O3) and Zirconium Oxide (ZrO2) and may be mono- or polycrystalline filled ceramic.
 10. The method according to claim 2, wherein the bracket is less than 3.00 mm thick from a nearest tooth bonding surface to entry of a slot.
 11. The method of claim 1, wherein the 3D CAD model is saved as a 3D vector file format.
 12. The method of claim 1, wherein different light curing strategies (LCSs) and depths of cure (Cd) are used.
 13. The method of claim 1, wherein a selection of glass or oxide ceramic filler material for producing layers of the bracket is based on different force demands.
 14. The method of claim 2, wherein printed bracket guides have a single bracket attachment for a single bracket.
 15. The method of claim 1, wherein an adhesive material is used to hold the bracket on a ceramic archwire.
 16. The method of claim 15, wherein the adhesive material is sticky wax.
 17. The method of claim 1, wherein indirect bonding/custom bracket placement occurs via a tray (for example, a silicone based, foam or vacuum formed tray) that carries the said custom ceramic brackets to the ideal tooth location.
 18. The method of claim 1, wherein the printed brackets have a metal insert that contacts an archwire in the slot so as to the reduce friction in the slot of a metal wire.
 19. The method of claim 1, wherein the printed brackets are of a twin design or are modified to be self-ligating or active ligating and are designed to accommodate 0.018 inch or 0.022 inch archwires in a slot, but slot height may vary from 0.018-0.022 inches.
 20. The method of claim 1 wherein the bracket angulation, offsets, torque, and prescription are determined based on a chosen treatment.
 21. The method of claim 1 wherein the structural properties of the base are selectively weakened to facilitate predictable and easier debonding of the bracket from a tooth following treatment.
 22. The method of claim 1, wherein a part of the bracket is a pre-formed green ceramic body that functions to decrease the time and complexity of the printed bracket.
 23. The method of claim 1, further comprising: producing a bracket guide comprising a rigid ceramic rectangular archwire or other archform that dictates a position of each bracket on a tooth in every plane with at least two occlusal/incisal supports adapted to help place brackets via an indirect bonding system.
 24. The method of claim 1, wherein a bracket pad or base plate) that holds or connects the bracket to the tooth surface is designed based on a surface profile of the tooth.
 25. The method of claim 1, wherein polycrystalline ceramic brackets have a color that is matched to a color of a tooth to which the bracket is to be attached and monocrystalline ceramic brackets are designed to be more translucent.
 26. The method of claim 1, wherein the bracket has a selected color unrelated to a color of a tooth to which the bracket is to be attached.
 27. The method of claim 1, wherein the DLP machine includes a light source that is a laser or LED light source.
 28. The method of claim 1, wherein a light source of the DLP machine radiates a wavelength between 400 and 500 nm.
 29. The method of claim 1, wherein the DLP machine includes a digital light processing chip as light modulator.
 30. The method of claim 29, wherein the digital light processing chip is a micromirror array or an LCD array.
 31. The method of claim 1, wherein measuring dentition data is performed using a CBCT scanner, intra-oral scanner, a coordinate measuring machine, a laser scanner, a structured light digitizers or a combination thereof.
 32. The method of claim 1, wherein measuring dentition data is performed by conducting 3D scanning on a casted or 3D printed teeth model.
 33. The method of claim 1, wherein the light-polymerizable material is selected from the group consisting of high strength Oxide ceramics including Aluminum Oxide (Al2O3) and Zirconium Oxide (ZrO2).
 34. The method of claim 1, wherein a slot position relative to the tooth may be customized by manufacturing a custom base or by manufacturing a custom slot position where a base is unchanged. 